The prostate is unique to the male of the species and consists of a mass of highly glandular tissue located just below the urinary bladder. The urethra exits the bottom of the bladder via a short neck which connects with the prostate. The prostate is bounded at the top by the involuntary sphincter and at the bottom by the voluntary sphincter and serves an important role in the production of seminal fluid during intercourse. The shape of the prostate has been compared to a chestnut, or a small turnip. It has a normal diameter of an inch and a half, and about an inch in length from top to bottom. The prostate consists primarily of numerous small glands that are bunched together in two large lateral lobes and a smaller middle lobe.
In cross section, the prostate normally shows a triangular arrangement with the two lateral lobes, appearing almost circular in section, lying on either side of the urethra on the side closest to the rectal wall, and a middle lobe being smaller and nestling between the lateral lobes on the front side of the prostate. The entire organ is encased in a tough muscular sheath, and is attached via a short neck to the base of the urinary bladder. The neck passes through a sheet of muscle, forming the involuntary sphincter, that underlies the fascia covering the bottom of the abdominal cavity. The bladder lies above the fascia within the abdominal cavity, and the prostate lies just below that fascia. As the urethra leaves the prostate it passes through another sheet of muscle, which forms the voluntary sphincter, and then into the penis. The retention of urine in the bladder is controlled by the two sphincters, voluntary and involuntary. The involuntary sphincter is the primary mechanism responsible for continence as it constricts the urethra and prevents the leakage of urine at volumes too low to be noticeable by the individual and during sleep. The voluntary sphincter acts as a secondary backup when there is a large quantity of urine. Urination is effected by a relaxation of both the sphincters combined with muscular contraction of the bladder and aided by gravity.
It has been estimated that, with advancing age, as many as 80% of all men will be affected by prostate problems. The primary prostate problem encountered is enlargement of the prostate, or Benign Prostatic Hyperplasia (BPH). The symptoms of BPH start with difficulty in voiding, difficulty in voiding completely, frequent urination (interruption of sleep), urinary tract infections from pooling of the urine, and can progress to over distention of the bladder, and kidney failure. In an individual suffering from BPH, excess tissue growth within the prostate applies pressure to the urethra, constricting the normal flow of urine, potentially to the point of complete blockage.
In this situation, muscular contraction of the bladder cannot overcome the constriction to force the urine through, because of the nature of the mechanical relationship of the bladder and the prostate. When the bladder contracts, it pulls down toward the base. Because it is anchored only at the base, it pulls against that anchor. The prostate is, in effect, that anchor. Normally, both sphincters relax, there is no constriction of the urethra, and the urine flows. However, when BPH is present, it acts like a sphincter which never relaxes. Therefore, the pressure generated by the bladder is also applied to the prostate (and thus to the BPH) in an additive manner. Pressure generated by the bladder and transferred to the prostate is applied equally to the BPH, so no matter how much pressure is generated by the bladder, and it can be enough to cause the bladder to bulge into pockets between the muscle bundles, it cancels out so the flow of urine is still blocked according to the degree of constriction caused by the amount of BPH present.
BPH in the majority of cases involves the middle lobe of the prostate which cannot be examined through the digital rectal approach. Diagnosis is entirely dependent on the symptoms. There is also no current technology to permit the physician to actually measure the pressure or the volume of BPH present within the prostate.
In addition to BPH, another abnormal condition that may be found within the prostate is the presence of a tumor. The symptoms of BPH are clear and obvious, and the physician can make a general diagnosis on the basis of patient response to questions. Diagnosis of the presence of a tumor, particularly in the early stages, is presently exceedingly difficult to achieve with any degree of reliability. Digital examination through the rectum is used to check the lateral lobes of the prostate for the presence of nodules. If a tumor is large enough, and in an accessible location it can be felt by the examining physician. The middle lobe of the prostate is not accessible via this approach. There is a blood test to detect the presence and amount of a substance called prostate specific antigen, (PSA) which is used to calculate the probability of the presence of cancer within the prostate. However, its use as a screening tool is controversial, and its reliability as a diagnostic tool is not high.
There are Endo-Rectal Ultrasound devices available at this time that can be pressed against the area of the rectum closest to the prostate to provide a means of scanning the prostate to look for signs of cancer. This method also is controversial owing to the difficulty in interpretation of the data. Either digital or endo-rectal ultrasound can be used to guide a biopsy needle to the suspected location. This is a difficult procedure however, as it is done without being able to see where the needle is to be inserted.
During patient evaluation for suspected prostate problems, a cystoscope is usually passed through the urethra into the bladder to assess the general condition of the uro-genital tract. Current cystoscopes are limited to purely visual inspection and add nothing to the physicians' arsenal of tools for the detection of cancer in the absence of an obvious lesion of the urethral wall or a visible mass in the bladder. If a tumor is suspected in any examination a biopsy is made through the rectal wall. None of these procedures have a good track record for accurate diagnosis of the presence of prostate cancer, particularly in the early stages.
If the diagnosis is BPH, there are a limited number of treatments available. In some cases of mild BPH, drug treatment and/or dietary modification may temporarily alleviate the symptoms. Also, there is a treatment for BPH, similar to balloon angioplasty, where the tissue is over-distended mechanically. This, too, is a temporary solution. The best and most common treatment is surgical intervention, generally, the TransUrethral Resection (TUR). In this method, a modified cystoscope, fitted with electrical or mechanical cutters, is introduced into the prostate via the urethra. This device is used to cut away the BPH tissue from the inside of the prostate.
If cancer were to be discovered at an early enough stage, a TUR could be employed to excise that as well. If the tumor is not detected at an early enough stage, treatment will involve the complete removal of the prostate, the lymph nodes of the groin, and possibly, the testicles. The simplest of these procedures involves an operation lasting up to an hour and a half, probably radiation treatment, and secondary complications. The most common secondary complication is the loss of fertility due to retrograde ejaculation. Also, radiation therapy, or mechanical trauma to the muscles can render the sphincters ineffective, thus making the patient incontinent.
The mechanism of retrograde ejaculation is as follows: The urethra, tightly constricted where it passes through the involuntary sphincter, after leaving the bladder opens up with the prostate into roughly a spindle shape. This shape is distorted in the upper region of the prostate by the presence of a longitudinal ridge, called the verumontanum, on one side of the urethra, which makes the urethral opening a "V" shape. This structure is thought to have the function of closing off the pathway to the bladder during ejaculation, thereby forcing the seminal fluid to exit via the penis. The ejaculatory ducts, which bring the sperm into the prostate, empty into the lower portion of the urethra below this area. The glandular tissue that makes up the prostate secretes the necessary seminal fluid to make up the rest of the ejaculate.
A TUR procedure normally destroys the verumontanum structure, permitting the retrograde flow of semen into the bladder. There is little or no semen ejaculated during orgasm, rendering the patient infertile. Although the sensation is said to be the same, the lack of ejaculate may have an adverse psychological effect on some individuals.
In summation; prostate problems are widespread in the older male population. The most common problem is enlarged prostate due to the presence of Benign Prostatic Hyperplasia tissue growth in the middle lobe of the prostate. Prostate cancer is also widespread and much more difficult to diagnose. At present, the best choice for treatment of either BPH or prostate cancer is, which type of surgery will be employed? Dilation and/or drug therapy may be able to temporarily relieve the symptoms but cannot correct the situation. The most popular surgery (TUR) is expensive, with an extended recovery time, no guarantee of permanence, it generally renders the patient infertile, and sometimes incontinent.
There is thus a definite need in the art for an alternate, more effective procedure for detecting, evaluating, and treating BPH and cancer of the prostate. Patents have been granted for "stents" that can be implanted in the prostate to hold open the lumen of the urethra without the necessity for surgery. However, these patented devices serve more in the nature of a stop-gap measure than an effective treatment. None of the patented stents are practically removable should the need arise. None of the patented stents offer any accommodation for variations between individuals. None of the patented "stents" has attempted to take a comprehensive approach to the problem. None of the current approaches enhances the physician's ability to detect, diagnose or quantify the status and progression, or treat abnormalities found in the prostate of a patient.
Accordingly, it is an object of the present invention to provide an accurate, cost effective, system and process for detecting, diagnosing, quantifying the status and progression, as well as treating of any abnormalities found in the prostate of a patient.
It is a further object of the present invention to provide a system for detecting, evaluating and treatment of Benign Prostatic Hyperplasia (BPH) in the prostate of a patient.
A further object of the present invention is a system that serves to provide a dimensional profile of the prostate to permit custom fabrication of a reinforcement insert for a specific patient.
A further object of the present invention is a system that measures the radial pressure within the prostatic urethra and provides the measured pressure in tabular form, relative to the dimensional profile of the prostate, to permit custom design of an implantable reinforcement insert for that individual.
A further object of the present invention is to provide a biocompatible reinforcement insert, custom fitted to the individual, that will maintain the lumen of the prostate open without the necessity for surgical removal of BPH tissue.
A further object of the present invention is an instrument for laying in place a custom made reinforcement insert within the prostatic urethra of an individual and for removal of that reinforcement insert when desired.
Still another object of the present invention is to provide a custom designed reinforcement insert for the prostatic urethra that includes a one way valve, permitting flow of fluid out of the bladder but not back into the bladder.
Still another object of the present invention is to provide a custom designed reinforcement insert for the prostatic urethra that includes a rotary valve that can serve to restore continence to individual patients wherein damage to the sphincter muscles has rendered that patient incontinent.
A further object of the present invention is a system that provides the capability of ultrasonically mapping from within the prostatic urethra the location and volume of any abnormality that may be present.
A further object of the present invention is a system that provides the capability of ultrasonically mapping from within the prostatic urethra, the tissue volume of the prostate at frequencies high enough (up to 50 MHz) to give sufficient resolution to permit diagnosis of malignancy of detected tumors.
Still another object of the present invention is an apparatus and process for providing radioactive treatment to the immediate area of a prostatic cancer, and the removal thereof at expiration of the desired application time.